This is a, to me, novel concept: Defence of design decisions or ‘why did we do it like this’.
I have never been involved with a large-scale project that didn’t have seemingly-weird decisions (and I’ve contributed my fair share), and an explanation would probably have helped.
The only problem I see will be in identifying them before it’s too late (and you forget why), but the presence of such a document surely shouldn’t hinder that.
In a sense this is the “comments should explain why not what“ maxim extracted into a document.
Via Hillel Wayne